Range limiting device for exercise machine

ABSTRACT

A range-limiting device allows a user to establish a range of motion, while maintaining the proper mechanical advantage provided by the cam assembly. The range-limiting device includes a shaft containing a lever and a cam disposed thereon. The radial orientation of the lever with respect to the cam is selectable, such that the effective radius of curvature of the cam with respect to the lever is automatically changed as the radial orientation is changed. The range-limiting device is operatively connected to an exercise machine, such that a lever is connected to the shaft, for rotation of the shaft, and the cam is connected to a resistance mechanism.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is related to and claims priority to U.S.Provisional Application Serial No. 60/338,035, filed Nov. 13, 2001,entitled LEG EXTENSION EXERCISE APPARATUS, the entirety of which isincorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] n/a

FIELD OF THE INVENTION

[0003] The present invention relates to exercise equipment, and moreparticularly to a device for adjusting the range of motion of exercisemachine moveable components.

BACKGROUND OF THE INVENTION

[0004] Selectorized weight machines have been used in fitness clubs andathletic facilities for many years. These machines allow the user toselect the weight to be lifted during a certain exercise or trainingprotocol.

[0005] One type of a selectorized weight machine allows forvariable-resistance along the range of motion of the exercise beingperformed. These selectorized, variable-resistance machines use a camhaving a variable radius or cam profile. A tether, such as a wire cable,a chain, a belt, or the like is attached at one end to a weight stackand is attached at the other end to the cam. The changing cam profilevaries the mechanical advantage in an attempt to approximate the changein anatomical mechanical advantage for the user at different points of arange of motion.

[0006] For example, when a user is at a “weak” point, where the user isunable to lift much weight, the cam profile will minimize the mechanicaladvantage that the weight stack has on the user. Similarly, at a user's“strong point”, the cam profile is configured to maximize the mechanicaladvantage that the weight stack has on the user. This process isaccomplished by varying the radius of the cam profile such that in theideal situation, the user is lifting as much weight he or she can ateach point in the user's range of motion.

[0007] The “selectorized” aspect of selectorized, variable-resistanceexercise machines allows the user to select a desired number of weightplates from a stack of plates, that the user wishes to engage or liftfor a particular exercise. The desired number of plates is typicallychosen by the user, by inserting a pin through a hole in a rod thatpasses through all of the plates, thus establishing plates above the pinas the weight load. Selectorized, variable-resistance weight machinesare well known art.

[0008] Selectorized, variable-resistance weight machines are used in therehabilitation field, as well as for exercise and training. Forrehabilitation purposes, it is often important to limit the range ofmotion for the patient. For example, after certain knee injuries, it isimportant that the patient avoid loading muscles with weights at certainpoints in the range of motion. However, for other points in the range ofmotion, use of a weight machine may play an important part in therehabilitation routine. Thus, selection of the correct start and stoppoint in the range of motion is critical to prevent injury. Sportsmedicine and rehabilitation physicians and physical therapists have longrecognized that there are certain safe ranges of motion forrehabilitation for certain injuries, and that the use of selectorizedvariable-resistance exercise machines can aid in rehabilitation withinthe critical range limits.

[0009] However, when selecting a range of motion, the cam profile mayprovide inefficient, and sometime undesirable, loads for a selectedrange of motion. For example, during certain muscular jointrehabilitation therapies, maximum loading may be applied atinappropriate points, resulting in an ineffective therapy, or provideadverse results.

[0010] Thus, there remains a need for a simple range-limiting device andadjustable cam device for exercise machines that can easily provide theappropriate range of motion and desired mechanical advantageconfiguration.

SUMMARY OF THE INVENTION

[0011] The subject invention provides a range-limiting device for usewith an exercise machine. The range-limiting device allows a user toestablish a range of motion, while maintaining the proper mechanicaladvantage provided by the cam assembly.

[0012] The range-limiting device includes a shaft having a cam and alever disposed thereon. The range-limiting device is operativelyconnected to an exercise machine, wherein the lever is used for rotationof the shaft within the exercise machine and the cam is connected to aresistance mechanism. The radial orientation of the lever with respectto the cam is selectable, such that the effective radius of curvature ofthe cam with respect to the lever is automatically changed as the radialorientation is changed. Additionally, a plate is pivotally mounted aboutthe shaft, where the plate limits the radial range of motion of thelever.

[0013] An exemplary exercise machine includes a support frame, where theshaft is pivotally mounted to the support frame. The cam is astart-positioning device, including an eccentric plate affixed to theshaft and an adjustable cam configured for receiving the eccentric plateand rotateably mounted about the eccentric plate. A cam plate isattached to the adjustable cam, wherein the cam plate is selectivelyengageable with the eccentric plate. The resistance mechanism isoperably connected to the adjustable cam.

[0014] The plate is an end-positioning device configured to beselectively engageable with the support frame, where the end-positioningdevice can be used to adjust the stop position of the lever. Theend-positioning device and start-positioning device are used inconjunction to vary the start and stop positions of an exercisemovement, while maintaining the correct mechanical advantage for therange.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] A more complete understanding of the present invention, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

[0016]FIG. 1 is a perspective view of the range-limiting device of thesubject invention;

[0017]FIG. 2 is a perspective view of a leg extension machine of thesubject invention;

[0018]FIG. 3 is a front view of a leg extension machine of the subjectinvention;

[0019]FIG. 4 is a side view of a leg extension machine of the subjectinvention;

[0020]FIG. 5 is a left side perspective view of the start-positioningdevice of the subject invention;

[0021]FIG. 6 is a right side perspective view of the start-positioningdevice of the subject invention; and

[0022]FIG. 7 is a perspective view of a leg curl machine for the subjectinvention.

DETAILED DESCRIPTION OF THE INVENTION

[0023] The subject invention provides a range-limiting device for usewith an exercise machine. As described herein, the range-limiting deviceallows a user to establish a range of motion, while maintaining aselected mechanical advantage provided by the cam assembly.

[0024] As shown in FIG. 1, the range-limiting device 10 includes a shaft12 having a cam 16 and a lever 18 disposed thereon. The range-limitingdevice 10 is operatively connected to an exercise machine, where thelever 18 is used for rotation of the shaft 12 within the exercisemachine and the cam 16 is connected to a resistance mechanism. Theradial orientation of the lever 18 with respect to the cam 16 isselectable, such that the effective radius of curvature of the cam 16with respect to the lever 18 is automatically changed as the radialorientation is changed. Additionally, a plate 14 is pivotally mountedabout the shaft 12, where the plate 14 limits the radial range of motionof the lever 18. The radial orientations of the plate 14 and cam 16 areindependently selectable, such that the reference points R1 and R2 areselectively rotateable with respect to each other. The particularorientation and spacing of the plate 14, cam 16, and lever 18 on theshaft 12 is for illustrative purposes only, and can vary depending onthe structural requirements of the exercise machine in which therange-limiting device 10 is being employed.

[0025] The range-limiting device 10 can be more fully understood whendescribed in conjunction with an exemplary exercise machine. As shown inFIG. 2, the exemplary exercise machine is a leg extension machine 20,having a support frame 22 on which a user support structure 24 ismounted. The user support structure 24 includes a seat surface 26 and anadjustable backrest 28. The adjustable backrest 28 can be adjusted in aforward and rearward direction, such that once the backrest 28 is in theappropriate position, the backrest 28 is secured in position by thebackrest adjustment mechanism 30.

[0026] An input assembly 32 is positioned in front of the seat 26, andmounted to the support frame 22 for rotation about a horizontal axisA-A, as defined by the range-limiting device 10. The input assembly 32includes a padded member 34 for a user's lower shins. A horizontal arm38 is disposed between the vertical arm 36 and a curved offset arm 40,where the curve offset arm 40 is affixed to the range-limiting device10, such that the padded member 34 is positioned in proximal relation tothe seat 26. (See also FIG. 3) A counterweight 42 is attached to therange-limiting device 10 to balance the input assembly 32 about thehorizontal axis A-A.

[0027] As shown in FIG. 3, the input assembly 32 includes an adjustablevertical arm 44, such that the padded member 34 can automatically bepositioned correctly on the lower shins of a user. The adjustablevertical arm 44 is slideably mounted within a collar element 48, suchthat the adjustable vertical arm 44 freely floats within the collarelement 48. As the user is positioned within the exercise machine, thepadded member 34 is automatically positioned against the user's shins.Optionally, the adjustable vertical arm 44 can be secured in positionwith locking element 50. A handle element 52 is affixed to theadjustable vertical arm 44 to aid in sliding the adjustable vertical arm44 through the collar element 42.

[0028] Referring again to FIG. 2, a weight stack brace 54 is attached tothe support frame 22 by beams 50 a and 50 b and secondary support frame58, such that the weight stack 60 is easily accessed by a user seated inthe seat 26. Weight stack pulleys 62 a and 62 b are mounted to the topof the weight stack brace 54, with pulley 62 a being aligned with therange-limiting device 10 and pulley 62 b being aligned with the weightstack 60. Rails 64 are mounted vertically within the weight stack brace54, where the individual plates of the weight stack 60 are slideablymounted to the rails 64 and provide a resistance to the exercise.

[0029] The weight stack 60 is selectively connected to one end of acable 70 by inserting a pin in one of a plurality of holes in a liftingpost 68 that passes vertically through the plates, as is well known inthe art. For example, the weight stack 60 is formed by a stack ofrectangular, brick-shaped plates 66. Each plate 66 further has at leastone horizontal channel or hole, wherein a pin may be disposed toslideably engage any of a series of horizontal channels which arevertically oriented on the lifting post 68 in a spaced apart manner tomatch the vertical spacing of the stacked weight plates 66. The pinthereby engages a portion of the stack of weight plates 66, such thatwhen vertical force is applied to the lifting post 68, the selectedstack of weight plates 66 is moved upwards to create a resistance.Typically, the weight stack 60 apparatus is oriented such that thefurther down the pin is entered into the lifting post 68, the greaterthe number of plates 66 are engaged, thereby increasing the resistanceof the machine.

[0030] The cable 70 extends up from the weight stack 60 and anintermediate portion of cable 70 extends over pulleys 62 a and 62 b. Thesecond end of the cable 70 is connected to the range-limiting device 10,thereby inhibiting rotation of the range-limiting device 10

[0031] Additionally, the weight stack 60 can be connected to therange-limiting device 10 by other means known in the art, including, butnot limited to, belts, cables, chains, or tethers, so as to inhibitrotation thereof.

[0032] In alternative embodiments, other mechanisms for providingresistance, such as friction fittings, springs, elastic bands, pneumaticor electromagnetic resistance, or an air resistance fan could beemployed (either alone or in combination) and still practice theinvention. Additionally, free weights could be operably engaged to theinput assembly 32 to resist the movement.

[0033] As shown in FIG. 2, the range-limiting device 10 includes ahorizontal shaft 72, defining the horizontal axis of rotation A-A, thehorizontal shaft 72 being pivotally connected to the support frame 22and the secondary support frame 58. An end-positioning device 78 and astart-positioning device 90 are affixed to the horizontal shaft 72. Theend-positioning device 78 includes a detent plate 80 having a horizontalstop 81, a handle element 82, and defining a plurality adjustment holes84. (See also FIGS. 3 and 4). The detent plate 80 is rotateably affixedabout the horizontal shaft 72 and affixable to the support frame's stoparm 86 by the engagement of stop pin 88 to one of the detent plate'sadjustment holes 84. The detent plate's vertical stop 81 is positionedfor engagement of the curved offset arm 40, where the horizontal stop 81limits the angle of rotation of the input assembly 32.

[0034] To adjust the input assembly's 32 stop position, the user graspsthe handle element 82 and disengages the stop pin 88 from the detentplate 80, rotating, pushing or pulling, the detent plate 80, about thehorizontal shaft 72, to the desired stop position. The stop pin 88 isreengaged with the detent plate 80, securing the horizontal stop 81 inthe desired stop position.

[0035] The detent plate's adjustment holes 84 are equally spaced, andmarker designations, such as the numbers “0” through “15,” are used toidentify the stop locations. The adjustment hole 84 locations “0”represent the approximate full range of motion (as that term isunderstood by therapists and clinicians) for various exercise andrehabilitation protocols. Use of the “0” designation allows thetherapist or clinician to quickly set the input assembly of the machineto the full range of motion.

[0036] As shown in FIGS. 5 and 6, the start-positioning device 90 isaffixed to the horizontal shaft 72, and includes a cam 92, eccentricplate 94, and a cam plate 96. The cam 92 is configured to receive theeccentric plate 94, such that the eccentric plate 94 is rotateablewithin the cam 92. The cam plate 96 is attached to the cam 92, sealingthe eccentric plate 94 within the cam 92, such that the cam 92 and camplate 96 are rotateable about the eccentric plate 94. The eccentricplate 94 includes a cam pin 100 for engaging the cam plate's adjustmentholes 98. The eccentric plate 94 is attached to the horizontal shaft'soffset mounting arm 104, such the axis of rotation of the eccentricplate 94 is offset from the eccentric plate's central axis.

[0037] The cam 92 and cam plate 96 have a variable radius profile whichchanges the mechanical advantage over the range of motion. The shape ofthe cam 92 and cam plate 96 attempt to match the change in anatomicalmechanical advantage at each point in the range of motion. The cam's 92profile depends upon the type of exercise or rehabilitation protocolcontemplated (e.g., leg extension, leg curl, arm curl, shoulder press,etc.) The manner in which the cam profile is established is well knownto those skilled in the art.

[0038] The inputs assembly's 32 start position is adjusted bydisengaging the input assembly 32 from the cam 92 and rotating, pushingor pulling, the input assembly 32 to the desired start position andreengaging the cam 92. To disengage the input assembly 32 from the cam92 the eccentric plate's cam pin 100 is disengaged from the cam plate96, allowing eccentric plate 94 to rotate within the cam 92 and camplate 96. The input assembly 32 is secured in the desired start positionby the cam pin 100 reengaging the cam plate 96, securing the eccentricplate 94 to the cam 92 and cam plate 96.

[0039] As noted above, the eccentric plate 94 is attached to thehorizontal shaft's offset mounting arm 104, such the axis of rotation ofthe eccentric plate 94, is offset from the eccentric plate's centralaxis. Accordingly, as the eccentric plate 94 rotates within the cam 92the radial positioning of the cam 92 about the horizontal shaft 72 ischanged, changing the effective radius of curvature of the cam 92 withrespect to the input assembly 32. The automatic change in the effectiveradius of curvature of the cam 92 provides an automatic change in themechanical advantage over the adjusted range of motion, thus providingthe correct anatomical mechanical advantage for the adjusted range ofmotion.

[0040] When the cam 92 is disengaged from the eccentric plate 94, thecam 92 is free to rotate in response to the tension in the cable 70. Asshown in FIG. 6, the rotation of the cam 92 is limited by the cam stop108 affixed to the secondary support frame 58 and the cam follower 106attached to the cam plate 96, where the cam follower 106 engages the camstop 108, preventing the cam 92 from rotating in response to the tensionon the cable.

[0041] The cam plate's adjustment hole 98 locations are equally spaced,and marker designations, such as the numbers “0” through “15,” are usedto identify the locations. The adjustment hole 98 locations “0”represent the approximate anatomical zero point (as that term isunderstood by therapists and clinicians) for various exercise andrehabilitation protocols. The cam plate's adjustment holes' 100 numbersenable the therapist or clinician to quickly set the input assembly 32to the anatomical zero position.

[0042] In an exemplary method of use, the end-positioning device 78 andthe start-positioning device 90 are used in conjunction to adjust theexercise start and stop positions. Initially, the user adjusts the startposition as noted above. In doing so, the effective radius of curvatureof the cam 92 is changed, providing the appropriated mechanicaladvantage for the new start position. The user can then adjust the stopposition as noted above, thereby provided a limited range of motion forthe exercise.

[0043] Referring now to FIG. 7, the present invention is shown in thecontext of a leg curl machine 110. In the leg curl machine 110, an inputassembly 112 is provided with two spaced pads for receiving a portion ofthe legs below the knees. The upper pad 114 engages the top of the legsjust above the knees while the lower pad 116 engages the back of thelegs just above the ankle area, wherein the lower pad 116 is mounted forrotation about a horizontal axis as defined by the range-limiting device10. To perform the exercise, the user places pressure on the lower pad116 with his legs to rotate the movement arm about the movement arm axisduring which time the upper pad 114 serves to maintain the properposition of the legs with the knees generally aligned with the pivotalaxis of the movement arm.

[0044] The above-described exercise machines are only exemplaryembodiments and should not be considered limiting to the types ofexercise machines the range-limiting device 10 can be incorporated into.For example, the range-limiting device 10 can be used in a variety ofpush or pull exercise machines, including but not limited to, chestpress machines, rowing machines, pull-down machines, back extensionmachines, arm extension and curl machines.

[0045] It will be appreciated by persons skilled in the art that thepresent invention is not limited to what has been particularly shown anddescribed herein above. In addition, unless mention was made above tothe contrary, it should be noted that all of the accompanying drawingsare not to scale. A variety of modifications and variations are possiblein light of the above teachings without departing from the scope andspirit of the invention, which is limited only by the following claims.

What is claimed is:
 1. An exercise machine comprising: a frame; a shaftpivotally mounted to the frame; a lever enjoining the shaft, forrotation of the shaft; a cam disposed on the shaft, wherein the radialorientation of the cam with respect to the shaft is selectable, suchthat an effective radius of curvature of the cam with respect to thelever is automatically changed as the radial orientation of the cam withrespect to the lever is changed and; a resistance mechanism operablyconnected to the cam.
 2. The exercise machine according to claim 1,further comprising a user support structure.
 3. The exercise machineaccording to claim 1, wherein the cam comprises: an eccentric plateaffixed to the shaft and an adjustable cam rotateably mounted about theeccentric plate, wherein the adjustable cam is selectively engageablewith the eccentric plate.
 4. The exercise machine according to claim 3,wherein the eccentric plate is attached to the shaft at an offsetdistance from a central axis of the eccentric plate.
 5. The exercisemachine according to claim 3, wherein the adjustable cam has a varyingradius profile.
 6. The exercise machine according to claim 1, furthercomprising a lever stop pivotally mounted on the shaft, wherein thelever stop is selectively engageable with the frame.
 7. The exercisemachine according to claim 1, wherein the lever is an input assemblyengageable by a user.
 8. An exercise machine comprising a range-limitingdevice comprising: a frame; a user support structure mounted to theframe; a shaft pivotally mounted to the frame; an end-positioning devicepivotally mounted to the shaft; a start-positioning device affixed tothe shaft; an input assembly affixed to the shaft, such that the inputassembly is in proximal relation with the user support structure; and aresistance mechanism operably connected to the start-positioning device.9. The exercise machine according to claim 8, wherein thestart-positioning device comprises: an eccentric plate affixed to theshaft; a cam configured for receiving the eccentric plate and rotateablymounted about the eccentric plate; and a cam plate attached to the cam,wherein the cam plate is selectively engageable with the eccentricplate.
 10. The exercise machine according to claim 9, wherein theeccentric plate is attached to the shaft at a distance offset from theeccentric plate's central axis.
 11. The exercise machine according toclaim 9, wherein the cam has a varying radius profile.
 12. The exercisemachine according to claim 8, wherein the end-positioning deviceincludes an input-assembly stop selectively engageable with the frame.13. A range-limiting device for use with an exercise machine comprising:a shaft; a lever enjoining the shaft, for rotation of the shaft; and acam disposed on the shaft, wherein the radial orientation of the camwith respect to the shaft is selectable, such that an effective radiusof curvature of the cam with respect to the lever is automaticallychanged as the radial orientations of the cam with respect to the leveris changed.
 14. The range-limiting device according to claim 13, furtherincluding lever stop pivotally mounted on the shaft, wherein the leverstop is selectively engageable to the exercise machine.
 15. Therange-limiting device according to claim 13, wherein the lever is aninput assembly engageable by a user.
 16. The range-limiting deviceaccording to claim 13, wherein the cam is connected to a resistancemechanism.
 17. The range-limiting device to claim 13, wherein the camcomprises: an eccentric plate affixed to the shaft; an adjustable camconfigured for receiving the eccentric plate and rotateably mountedabout the eccentric plate; and a cam plate attached to the adjustablecam, wherein the cam plate is selectively engageable with the eccentricplate.
 18. The range-limiting device according to claim 17, wherein theeccentric plate is attached to the shaft at a distance offset from theeccentric plate's central axis.
 19. The range-limiting device accordingto claim 17, wherein the adjustable cam has a varying radius profile.20. A start-positioning device for use with an exercise machinecomprising: an eccentric plate; a cam configured for receiving theeccentric plate, such that the cam is rotateable about the eccentricplate; and a cam plate affixed to the cam, wherein the cam plate isselectively engageable with the eccentric plate.
 21. An adjustable rangeof motion exercise device comprising: a user input structure selectivelypositionable to an approximate anatomical zero point; a cam coupled tothe user input structure, wherein the cam is adjustable to provide aselected mechanical advantage; and a resistance mechanism coupled to thecam.